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Title: CANDELS: THE EVOLUTION OF GALAXY REST-FRAME ULTRAVIOLET COLORS FROM z = 8 TO 4

Abstract

We study the evolution of galaxy rest-frame ultraviolet (UV) colors in the epoch 4 {approx}< z {approx}< 8. We use new wide-field near-infrared data in the Great Observatories Origins Deep Survey-South field from the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey, Hubble Ultra Deep Field (HUDF) 2009, and Early Release Science programs to select galaxies via photometric redshift measurements. Our sample consists of 2812 candidate galaxies at z {approx}> 3.5, including 113 at z {approx_equal} 7-8. We fit the observed spectral energy distribution to a suite of synthetic stellar population models and measure the value of the UV spectral slope ({beta}) from the best-fit model spectrum. We run simulations to show that this measurement technique results in a smaller scatter on {beta} than other methods, as well as a reduced number of galaxies with catastrophically incorrect {beta} measurements (i.e., {Delta}{beta} > 1). We find that the median value of {beta} evolves significantly from -1.82{sup +0.00}{sub -0.04} at z = 4 to -2.37{sup +0.26}{sub -0.06} at z = 7. Additionally, we find that faint galaxies at z = 7 have {beta} -2.68{sup +0.39}{sub -0.24} ({approx} -2.4 after correcting for observational bias); this is redder than previous claims in the literature andmore » does not require 'exotic' stellar populations (e.g., very low metallicities or top-heavy initial mass functions) to explain their colors. This evolution can be explained by an increase in dust extinction, from low amounts at z = 7 to A{sub V} {approx} 0.5 mag at z = 4. The timescale for this increase is consistent with low-mass asymptotic giant branch stars forming the bulk of the dust. We find no significant (<2{sigma}) correlation between {beta} and M{sub UV} when measuring M{sub UV} at a consistent rest-frame wavelength of 1500 A. This is particularly true at bright magnitudes, though our results do show evidence for a weak correlation at faint magnitudes when galaxies in the HUDF are considered separately, hinting that dynamic range in sample luminosities may play a role. We do find a strong correlation between {beta} and the stellar mass at all redshifts, in that more massive galaxies exhibit redder colors. The most massive galaxies in our sample have similarly red colors at each redshift, implying that dust can build up quickly in massive galaxies and that feedback is likely removing dust from low-mass galaxies at z {>=} 7. Thus, the stellar-mass-metallicity relation, previously observed up to z {approx} 3, may extend out to z = 7-8.« less

Authors:
 [1]; ; ;  [2];  [3];  [4]; ; ;  [5];  [6]; ;  [7];  [8]; ;  [9]; ; ;  [10];  [11];  [12] more »; « less
  1. Department of Astronomy, University of Texas at Austin, Austin, TX 78712 (United States)
  2. George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States)
  3. Physics Department, University of California, Santa Barbara, CA 93106 (United States)
  4. National Optical Astronomy Observatory, Tucson, AZ 85719 (United States)
  5. Space Telescope Science Institute, Baltimore, MD 21218 (United States)
  6. Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States)
  7. Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States)
  8. School of Physics and Astronomy, University of Nottingham, Nottingham (United Kingdom)
  9. Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh (United Kingdom)
  10. University of California Observatories/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States)
  11. Carnegie Observatories, Pasadena, CA 91101 (United States)
  12. Yale Center for Astronomy and Astrophysics, Departments of Physics and Astronomy, Yale University, New Haven, CT 06520 (United States)
Publication Date:
OSTI Identifier:
22092352
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 756; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTRONOMY; ASTROPHYSICS; ASYMPTOTIC SOLUTIONS; CORRELATIONS; COSMIC DUST; ENERGY SPECTRA; GALAXIES; GIANT STARS; LUMINOSITY; MASS; NEAR INFRARED RADIATION; RED SHIFT; ULTRAVIOLET RADIATION; ULTRAVIOLET SPECTRA; UNIVERSE

Citation Formats

Finkelstein, Steven L., Papovich, Casey, Salmon, Brett, Bassett, Robert, Finlator, Kristian, Dickinson, Mark, Ferguson, Henry C., Koekemoer, Anton M., Grogin, Norman A., Giavalisco, Mauro, Reddy, Naveen A., Mobasher, Bahram, Conselice, Christopher J., Dunlop, James S., McLure, Ross J., Faber, S. M., Kocevski, Dale D., Lai, Kamson, Hathi, Nimish P., Lee, Kyoung-Soo, and others, and. CANDELS: THE EVOLUTION OF GALAXY REST-FRAME ULTRAVIOLET COLORS FROM z = 8 TO 4. United States: N. p., 2012. Web. doi:10.1088/0004-637X/756/2/164.
Finkelstein, Steven L., Papovich, Casey, Salmon, Brett, Bassett, Robert, Finlator, Kristian, Dickinson, Mark, Ferguson, Henry C., Koekemoer, Anton M., Grogin, Norman A., Giavalisco, Mauro, Reddy, Naveen A., Mobasher, Bahram, Conselice, Christopher J., Dunlop, James S., McLure, Ross J., Faber, S. M., Kocevski, Dale D., Lai, Kamson, Hathi, Nimish P., Lee, Kyoung-Soo, & others, and. CANDELS: THE EVOLUTION OF GALAXY REST-FRAME ULTRAVIOLET COLORS FROM z = 8 TO 4. United States. https://doi.org/10.1088/0004-637X/756/2/164
Finkelstein, Steven L., Papovich, Casey, Salmon, Brett, Bassett, Robert, Finlator, Kristian, Dickinson, Mark, Ferguson, Henry C., Koekemoer, Anton M., Grogin, Norman A., Giavalisco, Mauro, Reddy, Naveen A., Mobasher, Bahram, Conselice, Christopher J., Dunlop, James S., McLure, Ross J., Faber, S. M., Kocevski, Dale D., Lai, Kamson, Hathi, Nimish P., Lee, Kyoung-Soo, and others, and. 2012. "CANDELS: THE EVOLUTION OF GALAXY REST-FRAME ULTRAVIOLET COLORS FROM z = 8 TO 4". United States. https://doi.org/10.1088/0004-637X/756/2/164.
@article{osti_22092352,
title = {CANDELS: THE EVOLUTION OF GALAXY REST-FRAME ULTRAVIOLET COLORS FROM z = 8 TO 4},
author = {Finkelstein, Steven L. and Papovich, Casey and Salmon, Brett and Bassett, Robert and Finlator, Kristian and Dickinson, Mark and Ferguson, Henry C. and Koekemoer, Anton M. and Grogin, Norman A. and Giavalisco, Mauro and Reddy, Naveen A. and Mobasher, Bahram and Conselice, Christopher J. and Dunlop, James S. and McLure, Ross J. and Faber, S. M. and Kocevski, Dale D. and Lai, Kamson and Hathi, Nimish P. and Lee, Kyoung-Soo and others, and},
abstractNote = {We study the evolution of galaxy rest-frame ultraviolet (UV) colors in the epoch 4 {approx}< z {approx}< 8. We use new wide-field near-infrared data in the Great Observatories Origins Deep Survey-South field from the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey, Hubble Ultra Deep Field (HUDF) 2009, and Early Release Science programs to select galaxies via photometric redshift measurements. Our sample consists of 2812 candidate galaxies at z {approx}> 3.5, including 113 at z {approx_equal} 7-8. We fit the observed spectral energy distribution to a suite of synthetic stellar population models and measure the value of the UV spectral slope ({beta}) from the best-fit model spectrum. We run simulations to show that this measurement technique results in a smaller scatter on {beta} than other methods, as well as a reduced number of galaxies with catastrophically incorrect {beta} measurements (i.e., {Delta}{beta} > 1). We find that the median value of {beta} evolves significantly from -1.82{sup +0.00}{sub -0.04} at z = 4 to -2.37{sup +0.26}{sub -0.06} at z = 7. Additionally, we find that faint galaxies at z = 7 have {beta} -2.68{sup +0.39}{sub -0.24} ({approx} -2.4 after correcting for observational bias); this is redder than previous claims in the literature and does not require 'exotic' stellar populations (e.g., very low metallicities or top-heavy initial mass functions) to explain their colors. This evolution can be explained by an increase in dust extinction, from low amounts at z = 7 to A{sub V} {approx} 0.5 mag at z = 4. The timescale for this increase is consistent with low-mass asymptotic giant branch stars forming the bulk of the dust. We find no significant (<2{sigma}) correlation between {beta} and M{sub UV} when measuring M{sub UV} at a consistent rest-frame wavelength of 1500 A. This is particularly true at bright magnitudes, though our results do show evidence for a weak correlation at faint magnitudes when galaxies in the HUDF are considered separately, hinting that dynamic range in sample luminosities may play a role. We do find a strong correlation between {beta} and the stellar mass at all redshifts, in that more massive galaxies exhibit redder colors. The most massive galaxies in our sample have similarly red colors at each redshift, implying that dust can build up quickly in massive galaxies and that feedback is likely removing dust from low-mass galaxies at z {>=} 7. Thus, the stellar-mass-metallicity relation, previously observed up to z {approx} 3, may extend out to z = 7-8.},
doi = {10.1088/0004-637X/756/2/164},
url = {https://www.osti.gov/biblio/22092352}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 756,
place = {United States},
year = {Mon Sep 10 00:00:00 EDT 2012},
month = {Mon Sep 10 00:00:00 EDT 2012}
}